Stress Response May Be Linked to Genotype Differences

Each student was then asked to provide an oral sample for genotyping of the brain-derived neurotrophic factor (BDNF) gene, which is involved in supporting the growth and differentiation of brain cells. This gene was of interest, since animal studies have shown that BDNF expression is reduced in chronic stress situations and restored by antidepressant treatment. In addition, each student's blood pressure and heart rate were monitored during the test.

Results published in the April 2009 issue of the journal Psychoneuroendocrinology revealed that in male subjects, those who were homozygotes for the BDNF valine/valine genotype showed a greater rise in salivary cortisol than did valine/methionine heterozygotes. In female subjects, there was a trend for the opposite response. Overall, the same pattern of results was observed for blood pressure and heart rate.

The investigators summed up the significance of these results: "The study specifically indicates that women with the BDNF Valine/Methione genotype and men with the Valine/Valine may be particularly vulnerable to social stress mediated by brain stress system activity."

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